Only question I have is how hard is it to either add a spacer or turn off the CEL for the catless? Is it just a coding issue and take 15minutes to deal with or is it a true ECU change?

Challenge, would I still see 10-15hp/tq with stock exhaust and the catless? (hypothetical, I won't quote you on it)

We havent played with any spacers onthe catless model yet There isnt alot of room to fit some of the spacers as well. We generally prefer to do it with software as a more consistant solution. The 335 is still lacking in some ECU options but im sure more will come with time.

our testing with the catless downpipe is limited right now as far as gains with a stock exhaust mostly due to the lack of ECU support. 10-20 hp/tq would be a pretty safe estimate though